"Believe in something. Even if it means sacrificing everything," the caption read in the black and white ad featuring Kaepernick's face.

Following the news, a number of people have filmed videos of themselves burning their Nike apparel, while others have suggested Tillman, who left the NFL to serve in the U.S. Army and was killed in Afghanistan in 2004, would make for a better spokesperson. An alternate, fictional Nike ad featuring Tillman's face circulated online Monday.

Pat Tillman was a NFL football player that quit the NFL to join the army after 9/11. In 2004 he died in Afghanistan due to friendly fire. pic.twitter.com/qUbOYn7R87

"In response to the Nike ad that is circulating. Please do not use Pat Tillman as a ploy for your political views," Staat, a former ASU and NFL defensive lineman, wrote in a Facebook post on Tuesday. "Pat was not a conservative [R]epublican, he did not believe in the Iraq War, he was not a Christian, and with the government and military handling of his death and the lies that followed I do believe that Pat would value the players' protest against police brutality and inequality."

Staat also asked people who plan to burn their Nike apparel to instead donate it to a local veterans organization.

Staat was a close friend of the late Tillman, who starred at ASU and for the Arizona Cardinals before leaving the NFL to join the Army in 2001.

Like Tillman, Staat wanted to leave pro football in order to enlist in the armed forces after the Sept. 11 terror attacks. Tillman convinced Staat to remain in the NFL until he was eligible for retirement benefits, but after Tillman died, Staat followed in his friend's footsteps
by enlisting in the U.S. Marine Corps in 2006, and he did a seven-month tour in Iraq in 2007.

Kaepernick was released by the 49ers after the 2016 season, but since that time, hundreds of NFL players have followed suit by protesting during the anthem in some form, especially after President Trump called last year for NFL players who sit or kneel during the anthem to be "fired."